Refrigeration method and apparatus



June 15, 1965 w. H. HOGAN REFRIGERATION METHOD AND APPARATUS 4 Sheets-Sheet 1 Filed Nov. 12, 1963 Walter H. Hogan INVEN TOR June 15, 1965 w, HOGAN I 3,188,819

REFRIGERATION METHOD AND APPARATUS Filed Nov. 12, 1963 4 Sheets-Sheet 2 STEP I I STEP 2 I STEP 3 STEP 4 UP I I I I I I I DISPLACER DOWN I I I I OPEN I REFRIGERATOR INLET VALVE CLOSED OPEN REFRIGERATOR EXHAUST VALVE CLOSED I OPEN I I I DRIVING MEANS I I INLET VALVE CLOSED I 1 I I OPEN I I I I I DRIVING MEANs I I I EXHAUST VALVE CLOSED I I I IF I I PRESSURE IN I L REFRIGERATOR I L P I I I STEP I I STEP 2 STEP 3 STEP 4 Walter H. Hogan I NVENTOR 3%; 4 [W AI orney W. H. HOGAN REFRIGERATION METHOD AND APPARATUS June 15, 1965 4 Sheets-Sheet 3 Filed Ndv. 12, 1963 Walter H. Hogon INVENTOR United States l atent O 3,188,819 v REFRIGERATION METHQD AND APPARATUS Walter H. Hogan, Wayland, Mass, assignor to Arthur D. Little, Inc., Cambridge, Mass, a corporation of Massachusetts Filed Nov. 12, 1963, Ser. No. 322,782 17 Claims. (Cl. 62-6) This invention relates to method and apparatus for developing low temperature refrigeration.

The invention relates more specifically to a process and apparatus for producing net refrigeration in a system in which some of the work extracted from the compressing, cooling and expanding of a fluid is in the form of a thermal energy, wherein the fluid leaving the system is at a temperature higher than at which it entered the system. This application is a continuation-in-part of my copending application Serial No. 213,185, now US. Patent No. 3,115,016.

In United States Patent No. 2,966,035, issued to Gifford, there is described a refrigeration method and apparatus which is directed to a so called no-work cycle in which refrigeration is obtained by removing more sensible heat from a system than is taken into the system by the refrigerating fluid used. Although the cycle described in U.S.P. 2,966,035 has been found to be very successful in producing refrigeration, even as low as K., the method and apparatus of that cycle possesses an inherent disadvantage in that the equipment required to control of fluid and thus to achieve refrigeration by the method and cycle described is expensive and difficult to assemble.

In acopending application, Serial No. 322,790, filed in the name of Walter H. Hogan, there is described and claimed a refrigeration apparatus which constitutes an improvement over the basic no-work concept.

I have found that the no-work cycle and apparatus of U.S.P. 2,966,035, as well as the apparatus of the aboveidentified application, may be materially improved by the incorporation of a third chamber of variable volume into the refrigeration system and the employment of this third chamber as a part of the overall cycle to control and drive the displacer which in turn is responsible for the required volume variations and the delivery of refrigeration to an external load. The use of a third chamber to control and drive the refrigeration chambers makes it possible to employ a self-regulating valve system and in turn also makes it possible through pneumatic driving means to construct a fairly simple, inexpensive refrigeration device which may be either an open cycle or a closed cycle. Various modifications are possible in the method and apparatus making it feasible to control the temperatures which can be attained in the refrigeration apparatus and cycle as well as to adapt them to various uses.

Several examples of the use and value of a small, inexpensive refrigeration which may, if desired, be operated on shop compressed air may be cited. Most medical and biology laboratories require small amounts of lowtemperature refrigeration for such work as the preparation of tissues for microscopic examination and the freezing of solutions. Usually, refrigeration needs are met by liquid nitrogen or solid CO For those requiring large quantities of continuous refrigeration, this is not too diflicult. But, it is not easy to obtain just one liter of liquid nitrogen or one pound of solid CO and, if a small amount of cooling is desired continuously, for weeks around the clock, it is diflicult to arrange for this using cryogenic fluids or solids. Many experiments that require temperatures below 233 K. (40 C.)the nominal lower limit of Freon refrigerationrnust be performed at temperatures fixed by the refrigerant used, e.g.,

3,188,819 Patented JunelE-i, 1965 liquid nitrogen (about 77 K.) and solid CO (about 195 K.). Temperatures between K. and 230 K. have been diificult to realize experimentally.

It would therefore be very desirable to have available a small self-contained unit which could be plugged into the power supply or compressed-air line in the laboratory or shop and which would deliver the small amount of refrigeration needed at any temperature down to 100 K. at a moments notice, and if necessary hold it for weeks at a time. The refrigerator described herein can meet such a need for it may employ low-pressure compressed air both for motive power and for the refrigeration. It is portable, can be connected to a compressed-air line and is ready to use within a few minutes. This refrigerator may also be operated on cyrogenic fluids (e.g., nitrogen and helium) and be used in a closed system and to develop cryogenic temperatures.

It is therefore a primary object of this invention to provide a refrigeration method and apparatus which can be operated on a compressed fluid, which is inexpensive to construct and operate, and which at the same time achieves the advantages associated with the no-work cycle. It is another object of this invention to provide an apparatus of the character described which makes possible a small, inexpensive, efiicient refrigeration apparatus which has many and varied uses, including incorporation in a cold trap, the cooling of detection devices, and the use as a laboratory tool. Other objects of the invention will in part be obvious and will in part be ap; parent hereinafter.

The invention accordingly comprises the several steps and relation of one or more of such steps with respect to each of th others and the apparatus embodying features of construction, combinations of elements, and arrangement of parts which are adapted to effect such steps, all as exemplified in the following detailed disclosure, and the scope of the invention will be indicated in the claims.

For a fuller understanding of the objects of the invention, reference should be had to the following detailed description taken in connection with the accompanying drawings in which.

FIGS. 1-4 are simplified diagrammatic views of the apparatus of this invention illustrating the steps in the basic cycle;

FIG. 5 illustrates a typical operational sequence for the cycle of this invention showing the operation of the displacer and the valves, as well as the pressure variations in the refrigerator;

FIGS. 6-9 illustrate various modifications of the apparatus of this invention in diagrammatic form; and

FIG. 10 shows a typical embodiment, partially in crosssection, of a refrigerator constructed in accordance with this invention.

In FIGS. 1-4 for convenience in describing the cycle of this invention the apparatus is shown in simple form (the descriptions and discussion of various modifications along with a typical detailed embodiment will be discussed below). In FIGS. 1-4 the figure numbers refer to the steps of the cycle which will be described in detail below. In order to simplify the drawings and cycle presentation, the valves which are closed are indicated by an X in a circle, while those which are open are presented as an open circle and are labeled for ease of identification.

' Thus, for example, in FIG. 2 it will be seen that both high-pressure valves are open.

Turning now to FIG. 1, it is possible to identify the component parts of a typical refrigeration appaartus constructed in accordance with this invention. A fluid-tight enclosed space generally designated as 143 is made up of a lower or refrigeration section 11, and an upper or driving section 12. It will be appreciated that the terms 3 upper and lower are used in a relative sense, and that the refrigeration apparatus may be oriented in any manner, these terms being employed only to correspond to the orientation illustrated in the figures. Within the fluid-tight enclosed space is a displacer 13 conforming essentially to the configuration of the enclosed space and movable therein'in a manner to define first,'second and third chambers of variable volume, designated as 14, and 16, respectively. Chamber's 14 and 15 :rnay bec'onsidered as part of the refrigeration system while chamber 16 forms a driving chamber. Inasmuch as a pressure differential must exist between volumes 14 and 16; it is necessary to employ a fluid-tight seal 17 as indicated.

Inthe literal sense, displacer 13 is actually a combination of a displacerand-a piston; however, for convenience of description it is referred to hereinafter as a displacer. It will also be noted that although the apparatus of FIGS. 1-4, 6," 7 and 9 incorporate the no-wor'k principle (rejection of thermal enregy equivalent to refrigeration produced')',they also provide'for'the delivery of some deliberate nonthermal work external of the system, and are directed to method and apapratus'providing pneumatic driving means for this system. The apparatus of FIG.

operating condition, this first step sweeps the cooled expanded fluid from the cold chamber 15 back through the no-work principleas at least a portion of their operation, they may be considered as nc-work apparatus operating ona no-work cycle. 2 V

Associated with the refrigerator-is a high pressure fluid source 18 (e.g.', a compressed. gas such as air or helium) and a low 'pressure fluid reservoir 29 which may form a closed cycle or which may vent to the" atmosphere in an open cycle. In FIG. 1 a closed-cycle is illustrated, and in (and clean-up system if required) and a -conipressor 23 are' furnished. From high-pressure fluid source 18 there is a high pressure line 25, controlled by valve 26, which leads into a fluid conduit 27 communicating with the first chamber, 14 and second chamber 15, and also controlled by "valve 38which leads into fluid conduit 28 communicating with third chamber 16. Likewise, the low-pressure'reservoir has a fluid conduit 29, controlled by valve 30, communicating with the fluid conduit 27, and also controlled by valve 39 which also leads into conduit 28 and chamber 16. Fluid conduits Z7 and 32 make upa fluid path between the first chamber 14 and the second:

chamber 15; Incorporated as a portion of this fluid path is a heat storage means 34which is typically aregeneraf tor. Located influid conduit 32 is a refrigeration load 36 which may be a heat station or a heat exchanger capable of circulating a heat transfer fluid through a conduit 37 in out-of-contact heat exchange with cooled fluid flowing from'the second chamber 15 out through the'system into the low-pressure reservoir. p a

The temperature history diagram of the no-work portion of the cycle which is performed in this apparatus is essentially that'illustrated in U.S.P. 2,966,035. The operational sequence diagram forthe apparatus of this inventio'n includes that for the driving chamber 16 and is illustrated in FIG. 5. Using thisFIG. 5 with FIGS. 14,

it is possibleto describe the refrigeration and driving 13 is in its uppermost position. The high-pressure valve 38 associated with the driving chamber 16 is open, and the low pressure valve 30 associated with the refrigerator portion is open, a condition which forces the displacer downwardly. Assuming the refrigerator to be in normal heat exchanger 36 to deliver refrigeration and through the. regenerator 34 and into the low-pressure reservoir 20 and into chamber 14. During its discharge, the refrigeration fluid exchanges heat in the regene'rator and in doing so is warmed to a temperature above that at which the high-pressure fluid was originally supplied as will be explained subsequently. This dilferencein temperature is a measure of the amount of refrigeration extracted from the fluid. Once the displacer has reached its lowest position, as shown iii-FIG. 1B, step'2'is begun. In this step the high-pressure valve 26 into the refrigeration system is opened permitting high-pressure fluid to flow into chamber 1'4 and compress residual fluid left there. The high-pressure fluid also flows into conduit 32 and chamber 15. Theresidual fluid in chamber'14 is heated by this compression. The mixed temperature of thehigh-pressure fluid in chamber '14 :is therefore higher than the temperature of the incoming fluid; In this step, the displacer 13 dwells temporarily in this position by virtue of the fact that the high-pressure fluidvalve 38'is open to the third or driving chamber 16.

Step3 begins withithe closing of the high-pressure valve 38 and the opening of the low-pressure valve; 39 associated with the driving chamber 16, thus reducing the pressure in chamber 16 andbeginning the upward movement of the displacer'by virtue of the pressure differential which exists between chambers 15 athigh pressure and- 16 at low pressure. During step3 thefihigh-pressure valve 26 associatedwith the refrigerator portion of the apparatus remains open, thus permitting additional highwhich passes into the regeneratorfidand passes through it giving up heat to the cooler regeuerator matrix; and enters the cold charnber l5 as-high pressure, initially cooled fluid. As shown in' FIG. 5 in thed'otted line in the refrigerator inletvalve sequence diagram, it is p'o's sible'to close this high-pressure valve 26 in step 3 some "what before theend of the"step';i.e.=, some time'after chamber 15 has reached at least one-half its maxiinumvolume. Although leaving the high pressure valveJ26' open for the full stroke provides the greatestgross refrigeration, the regenerator losses-are "greatest. Closing the high-pressure valve 26 before'the' 'end' of step 3 provides less refrigeration, but also'less regenerator loss," which frequently results in more net refrigeration available for" less fluid circulation." Therefore, there "is offered an al ternative in the operation of thisihigh-press'ure valve in step 3." The effect which'this early cut-'otfof the highpressure valve 26 controlling the refrigeration fluid has upon thej pressure within the refrigeratoris' illustrated also In FIG. 5 by the dotted line.

expanded and further cooled during completion 'of" step 3. At'the'end'o'f stepB', the" displacer' 13 is" in its upper most position, the driving chamber "16 andvolufne of 7 chamber, 14 are" at aminimunywhile 'the'cold' chamber 15 has reached a'maxlmum volume and contains initialfluid, the pressure and the 'temperaturefdepending upon tllle 115116 at which thehigh-pressur'e -'v"alve 26 in step 3 was cOse- :7 v.

Step 4 comprises the opening of the low-pressure valve 1y cooled, (and perhaps further cooled) highpressure 30 associated-with'the refrigerator section to the low-" pressure reservoir 20' and the consequent expansion and further cooling of the fluid within chamber isan'a within the regenerator"34.' Withthe 'cornplet'ion of the expansion step 4, the high-pressure valve 38 associated with the driving chamber-1'6. is opened and the cycle is in a condltion to begin'with step 1 as illustrated in FIG. 1.

lfshould be noted that after early cut-off the fluid in cold' chamber 15'is It is now possible to describe step 1 more fully. At the beginning of step 1 the low-pressure fluid in chamber is at a lower temperature than that of the highpressure fluid that filled chamber 15 by virtue of the adiabatic expansion of the residual gas in chamber 15 from high pressure to low pressure. The high pressure in chamber 16, being in excess of the low pressure in chamber 15, forces the displacer 13 downwardly expelling the fluid in chamber 15 initially through heat exchanger 36. In this heat exchanger the temperature of the fluid can be raised to substantially the temperature of the fluid in chamber 15 before its expansion, thereby providing refrigeration to fluid in conduit 37 or to any other suitable heat source. The low-pressure fluid then enters the cold end of the regenerator 34 at substantially the same temperature as that of the high-pressure fluid leaving regenerator 34 during the pressurizing of chamber 15 in step 3. During passage of this fluid through the regenerator 34- heat is extracted from the regenerator matrix to increase the temperature of the fluid so that on leaving the regenerator 34 at the warm end the fluid temperature is substantially the same as that temperature of the entering high-pressure fluid during step 3 which, it will be remembered, was higher than the temperature of the high pressure fluid being supplied through conduit from high pressure fluid source 18. The fluid leaving regenerator 34 fills expanding chamber 14 with low pressure fluid and the excess leaves through low-pressure valve to be returned to the lower-pressure reservoir 20. Since this fluid leaves the refrigeration system at a higher temperature than the fluid supplied to the system, thermal energy is extracted from the system.

It has been pointed out that chamber 16 is a driving chamber and further explanation of its operation with reference to FIGS. 1-4 will be helpful. A portion of the cross-sectional area of the displacer 13 in chamber 15 can be considered equivalent and opposite to the crosssectional area of the displacer 13 in chamber 14. Because these two chambers 14 and 15 are connected through the fluid path comprised of conduits 27 and 32, it is obvious from the drawings that there will always be substantially fluid pressure equality within these two chambers; and therefore there exists no net force between these two chambers by virtue of these equivalent displacer cross-sectional areas. There is also in chamber 15 a cross-sectional area of displacer 13 which may be considered to be equivalent and opposite to the crosssectional area of the piston position of displacer 13 in chamber 16. Whenever there is a fluid pressure unbalance, brought about by the control of the valves, between the fluid in chamber 16 and in chamber 15 there is a net force operating on the displacer 13 which is equivalent to the difference in pressure between these two chambers multiplied by the cross-sectional areas of the displacer in chamber 16. Therefore by suitable control of the pressurization and depressurization of the fluids in these chambers, as described in the cycle steps, the displacer 13 can be made to move upwardly or downwardly or to dwell. Since chamber 16 is not part of the refrigeration system as are chambers 14 and 15, this chamber has been called the driving chamber.

FIGS. 6-9 illustrate four possible modifications of the apparatus which operate on the cycle described above. In FIG. 6, it will be seen that a separate fluid system is provided for the driving chamber 16. This separate system comprises a high-pressure source with a highpressure fluid line 41 controlled by valve 42; and a lowpressure reservoir 43 with a low-pressure fluid line 44 controlled by valve 45. This FIG. 6 (as Well as FIG. 8A) illustrates the incorporation of a secondary fluid path 46 containing a secondary regenerator 47. When this secondary fluid path is added to the apparatus of FIG. 8, then conduit 27 will not communicate with chamber 14.

In FIG. 7 the displacer is replaced by a separate displacer 48 associated with the refrigeration portion of the apparatus and a piston 49, the two being joined by suitable mechanical means such as shaft 50.

In FIG. 8 an additional annular seal 51 is added to isolate chambers 14 and 16, and at the same time to form an auxiliary first chamber 14a. In the operation of the refrigerator, chambers 14:: and 15 alternate in their functions, and when they are not performing the role as described above in connection with FIGS. 1-4, they are serving as bufler volumes, the purpose of which is to cushion the movement of the displacer or piston within the apparatus.

Finally, FIG. 9 illustrates a modification of this apparatus which provides for a series of successive colder chambers which in effect are equivalent to chamber 15 of FIG. 1. The refrigeration portion of the apparatus comprises a stepped enclosed space 53 containing therein an appropriate stepped displacer 54. The movement of this displacer defines three successively colder chambers 55, 56 and 57. The fluid path from the first chamber 14 to the series of second chambers is made up of conduits 6d, 61, a2 and 63, and contains three regenerators or heat storage means 65, 66 and 67. The refrigeration load 36 is seen to be associated with the last fluid conduit 63 which of course contains the coldest fluid. The regenerator or regeneratcrs do not have to be external of the cylinder, but may pass through the displacer or may be annular passages within the cylinder around the displacer. The modification of FIG. 9 may also, of course, incorporate the use of the annular seal 51 of FIG. 8.

In FIGS. 79 the chamber 16 is still the driving chamber as described with reference to FIGS. 14. In these modifications the cross-sectional area of the displacer 48 (or 54 in FIG. 9) in chamber 14 is equal to the crosssectional area of the displacer in chamber 15 (or chambers 55, 5:: and 57 in FIG. 9); and with equal fluid pressures in these chambers which exist by virtue of the fluid path, there exists no net force on the displacer tomove it. However, piston section 49 exists between chambers 14 and 16 and is connected to the displacer. When a pressure differential exists between chambers 16 and 14 because of the manipulation of the valves, a net force will be provided to move the displacer in the desired manner.

FIG. 10 illustrates one embodiment of the apparatus of this invention as constructed into a practical working laboratory refrigerator along the modification of FIG. 7, but using a single source of compressed fluid for the refrigeration and driving chambers and venting to the atmosphere. It will be appreciated that many variations of such apparatus are possible, and that the valving means illustrated are only one of a wide variety of valving systems available to one skilled in the art.

In the apparatus of FIG. 10 the refrigeration portion is enclosed in a cylinder block 71) which contains within it a separating wall 71, thus defining a refrigeration cylinder 72, which has a cylinder lining 73, and a volume suitable for the regenerator 34 which in this case is shown to consist of stacked copper screening 75. A block 77 encloses the bottom of the refrigeration section, while the top portion 78 contains within it a cylinder 79 forming that portion in which the piston 49 operates to define the driving chamber 15. The regenerator 34 terminates in a knurled heat station 82. An annular header 83, a shaft 34, a threaded portion 85, and a shaft 86 make up the means for delivering refrigeration to an external load. The regenerator is sealed Within the main cylinder block by means of a seal plug 87. A channel 88 (corresponding in this case to fluid path 32 of FIG. 1) communicates between the cold second chamber 15 and the header 83, thus the coldest fluid in the system is brought into contact with the shaft 84 and delivers refrigeration through thermal conductivity to the external shaft 86.

Fluid is introduced into the apparatus both for use in the refrigeration section and in the driving chamber a through a conduit 92, and this in turn communicates by channels (not shown) in the block 91 with the fluid conduit 27 designed to communicate with the first chamber 14, and through fluid conduit 28 which communicates with the third chamber or driving chamber 16. A shaft in the name of Fred F. Chellis and assigned tothe same assignee as the present application. However, other types of slide or spool'valves, rotary valves or poppet valves may be used, or the piston 49 may be driven by external means. The apparatus of FIG. with the valving means of application Serial No. 359,000 has the distinct advantage of being self-regulating and of operating without any external controls. I U I From theabove description of this invention, it will be seen that there is provided a novel refrigeration method and apparatus for carrying out the cycle 'of this method in an eflicient manner. Moreover, the apparatus is easily and inexpensively constructed,and readily lends itself to many variations and tea degree of flexibility normally not associated with refrigeration equipment. The

apparatus is equally adaptable to one-stage and multi-. stage operations, it maybe used with full or early cutofl of high-pressure fluid as described, and it is readily incorporated into other apparatus requiring refrigeration.

It will thus be seen that the objects set forth above,]

among those made apparent from the preceding description, are efliciently attained and since certain changes may be made in carrying out the above method and in tained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

I claim:

1. A method of producing refrigeration wtihin an enclosed space divided into first and second refrigerating chambers and a third driving chamber, each of variable volume, comprising the steps of (a) supplying high-pressure fluid from a high-pressure fluid source into said third chamber while simultaneously increasing the volume of said first and said third chambers and decreasing the volume of said second chamber, said first and second chambers 7 being connected by a fluid path;

(b) supplying high-pressure fluid togsaid first chamber from said high-pressure fluid source while continuing to supply high pressure fluid to said third chamber and compressing said fluid in said firstchamber thereby causing residual fluid in said first chamber to increase in temperature; g V (c) withdrawing high-pressure fluidfrom said third chamber into a low-pressure reservoir while simul taneously decreasing. the volumes of said first and third chambers, increasing the volume of said second chamber, continuing to supply high-pressure fluid for mixing with the high-pressure fluid of increased temperature from said first chamber, and transferring the resulting fluid mixture of intermediate temperature through said fluid path into said second chamber; and 7 g (d) withdrawing fluid from said second chamber through said fluid path into said low-pressure reservoir thereby effecting expansion and cooling of said fluid in said second chamber and said fluid path. 2. Method in aecordancewith claim 1 wherein the step of continuing to'supply high-pressure fluid in step (c) is carried out until the volume of said second chamber has reached at least one-half its maximum.

the construction set forth without departing from thescope of the invention, it is intended that all matter con-- 8 3.'A method of producing refrigeration w-ithin an enclosed space divided into first and second refrigerating chambers and a third driving chamber, each of variable volume, comprising the steps of a) supplying high-pressure fluid fror'na high pressure fluid source into said third chamber while simultaneously increasing the volume of said first and said third chambers and decreasing the volume of said second chamber, said first and second chambers being connected by a fluid path; a

(b) supplying high-pressure fluidto said first chamber from said high-pressure fluid sounce :while continuing to supply high-pressure fluid to said third chamber and compressing said fluid in said first chamber thereby causing residual fluid in said first chamber to increase in temperature;

(c) withdrawing the high-pressure fluid from said third chamber into a low-pressure reservoir while simultaneously decreasing the volumes of said first and third chambers, increasing the volume of said second chamber, continuing to supply high-pressure fluid for mixing with the high-pressure fluid of increased temperature from said 'fi'r-st chamber, and transferring the resulting fluid mixture of intermediate temperature through said fluid path into said second chamber while removing and storing heat from said fluid during said transfer; and, V

(d) withdrawing fluid from said second chamber through said fluid path into said low-pressure reservoir thereby effecting expansion and cooling of said fluid in said second chamber and said fluid path, said iiuid during said withdrawing receiving said heat previously stored in said fluid path.

4. A method of producing refrigeration within an'enclosed space divided into .a first warm chamber, a series of second cold chambers anda third driving chamber,

each of variable volume, comprising the stepsof (a) supplying high-pressure fluid from a high-pressure fluid source intosaid third chamber'while simultaneously increasing the volume of said first and said third chambers and decreasing the volume of each of said second chambers, said first and said second chambers being connected by a fluidpat-h;

(b) supplying high-pressure fluid to said first chamber from said high-pressure fluid source while continuing to supply high-pressure fluid to said third chamber and compressing said fluid in said first chamber thereby causing residual fluid in said first chamber to increase in temperature;-

(0) withdrawing highpressure fluid from said third chamber into a low-pressure reserovir while simultaneously decreasing the volumes of said first and third chambers, increasing the volume of said second chambers, and continuing to supply high-pressure fluid for mixing with the high-pressure fluid of increased temperature from said first chamber, and transferring the resulting fluid mixture of intermediate temperature through said fluid path into said second chambers while removing .and storing heat from said fluid during said transfer; and

(d) withdrawing fluid from said second chambers through said fluid path into said low-pressure reservoir thereby effecting expansion and cooling of said fluid in said second chambers and said fluid path, said fluid during said withdrawing receiving said heat previously stored in said fluid path.

5. The fluid refrigeration method comprising the steps of (a) supplying an initial quantity of a high-pressure refrigeration fluid to a first enclosed space of variable volume thereby increasing the fluid pressure therein and heating said initial quantity of fluid, while simultaneously maintaining high-pressure fluid in a third fluid-volume-contnollin-g enclosed space of variable a volume associated with said first enclosed space and with a second enclosed space of variable volume;

(b) Withdrawing high-pressure fluid from said third chamber into a low-pressure reservoir While simultaneously decreasing the volumes of said first and third chambers, increasing the volume of said second chamber, and continuing to supply high pressure fluid for mixing with the resulting heated initial quantity of fluid to form a fluid mixture at a temperature intermediate between that of said heated initial quantity and said additional quantity, while continuing to decrease the volume of said third enclosed space;

() supplying said fluid mixture to said second enclosed space, removing and storing heat from said fluid mixture along .a path during said supply to said second enclosed space thereby initially cooling the fluid and continuing to decrease the volume of said third enclosed space;

(d) continuing the supply of said fluid mixture throughout said initial cooling thereby to maintain said high pressure by addition of high-pressure fl-uid until .a final quantity of cooled fluid under said high pressure is supplied to said second enclosed space and decreasing the volume of said third enclosed space to a minimum;

(e) discontinuing supply of high pres-sure fluid to said first and second enclosed spaces;-

(f) effecting expansion of said final quantity of fluid in said second enclosed space there-by further to cool and extract energy from the fluid in said second enclosed space; and

(g) exhausting the further cooled. fluid from said second enclosed space through said path while increasing the volume of said first and third enclosed spaces by supplying high-pressure fluid to said third space, the further cooled fluid exhausted from said second enclosed space receiving heat previously stored along said path and leaving said path at a temperature very close to the temperature of said fluid entering said 19 V out said initial cooling thereby to maintain said high pressure by addition of high-pressure fluid until a final quantity of cooled fluid under said high pressure is supplied to said second enclosed spaces and decreasing the volume of said third enclosed space to a minimum;

(e) discontinuing supply of high-pressure fluid to said first enclosed space and to said second enclosed spaces;

(f) effecting expansion of said final quantity of fluid in said second enclosed spaces thereby further to cool and extract energy from the fluid in said second enclosed spaces; and

(g) exhausting the further cooled fluid from said second enclosed spaces through said path while increasing the volume of said first and third enclosed spaces by supplying high-pressure fluid to said third space, the further cooled fluid exhausted from said second enclosed spaces receiving heat previously stored along said path and leaving said path at a temperature very close tothe temperature of said fluid and above that of said initial quantity of said fluid whereby more heat is taken out than was brought in by said initial and additional quantities of fluid.

8. Method in accordance with claim 7 wherein the addition of high-pressure fluid in step (d) is carried out until the volumes of said second enclosed spaces have reached at least one-half their maximum.

9. Refrigeration apparatus, comprising in combination (a) cylinder means;

(b) displacer means movable Within said cylinder means;

(0) first and second refrigerating chambers and a third driving chamber, the volumes of which are defined by the movement of said displacer means such that when the volumes of said first and third chambers increase the volume of said second chamber decreases and when the volumes of said first and third chambers decrease the volume of said second chamber inpath and above that of said initial quantity of said 40 creases;

fluid whereby more heat is taken out tha was (d) a fluid path conecting said first and second chambrought in by said initial and additional quantities bers;

f fl id, (e) thermal storage means associated with said fluid 6. Method in accordance with claim 5 wherein the pa h;

(f) means for supplying fluid to and withdrawing fluid from said third driving chamber thereby to impart predetermined motion to said displacer means, the displacer motion being defined in four steps and consisting of dwelling in an uppermost position, moving downwardly, dwelling in a lowermost position, and moving upwardly, respectively;

(g) supply reservoir means for supplying high-pressure fluid to said chambers;

(h) exhaust reservoir means for receiving low-presaddition of high-pressure fluid in step (d) is carried out until the volume of said second enclosed space has reached at least onehalf its maximum.

7. The fluid refrigeration method comprising the steps of (a) supplying an initial quantity of a high-pressure refrigeration fluid to a first enclosed space of variable volume thereby increasing the fluid pressure therein and heating said initial quantity of fluid, while maintaining high-pressure fluid in a third fluid-volumecontrolling enclosed space of variable volume asso- Sure fluid from Said Chambers;

ciated with said first enclosed space and with a series first Valve means associated With Said pp and of second en lo ed a e f v i bl ol exhaust reservoir means and controlled to cause high- (b) ithd wi high-pressure fluid f o id thi d pressure fluid to enter said first chamber and said chamber into a low-pressure reservoir while simulfluid path during said third and fourth steps of said taneously decreasing the volumes of said first and isp er motion and to exhaust low-pressure fluid during said first and second steps of said displacer motion; and (j) second valve means associated with said supply and exhaust reservoir means and controlled to exhaust low-pressure fluid from said third chamber during said first and fourth steps of said displacer motion and to supply high-pressure driving fluid to said third chamber during said second and third steps of said displacer motion. 10. Refrigeration apparatus in accordance with claim 9 wherein said supply and exhaust reservoir means for supplying fluid to and receiving fluid from said first and second chambers are distinct from said supply and exhaust reservoir means for supplying and receiving fluid from said third chamber.

third chambers, increasing the volume of said second chambers, and continuing to supply high-pressure fluid for mixing with the resulting heated initial quantity of fluid to form a fluid mixture at a temperature intermediate between that of said heated initial quantity and said additional quantity, while continuing to decrease the volume of said third enclosed space;

(c) supplying said fluid mixture to said second enclosed spaces, removing and storing heat from said fluid mixture along a path during said supply to said second enclosed spaces thereby initially cooling the fluid and continuing to decrease the volume of said third enclosed space;

((1) continuing the supply of said fluid mixture through- 11. Refrigeration apparatus in accordance with claim 9 further characterized by having heat exchange means associated with said fluid path thereby to extract refrigeration from said apparatus.

12. Refrigeration apparatus in accordance with claim 9 wherein said displacer means'comprise's a displacer and a piston mechanically connected.

13. Refrigeration apparatus, comprising in combination (a). cylinder means;

(b) di-splacer means movable within said cylinder means;

(c) a first chamber, a series of second chambers, and a third chamber, said firstchamber and said series of second chambers forming the refrigeration portion of said apparatus and said third chamber the driving portion, the volumes of'each of said chambers being defined by the movement of said displacer means such that when the volumes of said first andthird chambers increase the volumes of said second chambers decrease and when the volumes of said first and third chambers decrease the volumes of said second from said third driving chamber thereby to impart predeterminedrnotion to said displacer means, the displacer motion being defined in four steps and consisting of dwelling in an uppermost'position, moving downwardly, dwelling in a lowermost position, and; moving upwardly, respectively; g) supplyreservoir means for supplying high-pressure fluid to said chambers; (h) exhaust reservoirmeans for fluid from said chambers; v (i) first valve means associated with said supply and exhaust reservoir means and controlled to cause highpressure fluid to enter said first chamber and said fluid path during said third and fourth steps of said displacer motion and to exhaust low-pressure fluid during said first and second steps of said displacer motion; and (j) second valve means associated with said supply and exhaust reservoir means and controlled to exhaust low-pressure fluid from said third chamber during said first and fourth steps of said displacer motion and to supply high-pressure driving fluid tosa'id third chamber during said secondand third steps of said displacer motion. 7 v

receiving, low-pressure 14. Refrigeration apparatus in accordance with claim (a) supplying high-pressure fluid from a high-pressure V fluid source into said third chamber While simultaneously increasing the volume of said first and said third chambers and decreasing the volumejof I 12 saidasecond chamber, said first and second chambers being connected by a fluid path;

(b) supplying high-pressure fluid to said first chamber from said high-pressure fluid source while maintaining high-pressure fluid in said third chamber and compressing said'fluid in said first chamberthereby causing residual fluid in said first chamber to increase in temperature;

(c) withdrawing the high-pressure fluid from said third chamber into a low-pressurereservoir-while simultaneously' decreasing the volumes of said first and third chambers, increasing the volume of said second chamber, continuing to supply high-pressure fluid for mixing with the highpressure fluid of increased 'temperature'from said first chamber, and transferring the resulting fluid'mixture of intermediate temperature through said'fluid path into said second chamber while removing and storing heat from said fluid during said transfer; and

(d) withdrawing fluid from said second chamber through said fluid path into said low-pressure reservoir thereby effecting expansion and cooling of said fluid in saidsecond chamber and said fluid path, said fluid during said withdrawing receiving said heat previously stored'in said fluid path.

17. A method of producing refrigeration within an enclosed space divided into a first warm chamber, a series of second cold chambers and a'third driving chamber, each of variable volume, comprising the stepsof (a) supplying high-pressure fluid from a high-pressure fluid source'int'o said third chamber while simultaneously increasing the volume of said first and said third chambers and decreasing the volume of each of said second chambers, said first and said second chambers being connected by a fluid. path;

. (b) supplying high-pressure fluid to said first chamber from said high-pressure fluid source while maintaining high pressure fluid in said third chamber and compressing said fluid in said firstchamber thereby causing residualfluid in said first chamber to increase in temperature;

(0) withdrawing high-pressure fluid from saidthird chamber intoa low-pressure reservoir while simultaneously decreasing the volumes of said first and third chambers, increasing the volume of said second chambers, and continuing to supply high-pressure fluidfor mixing with the high-pressure fluid of increased temperature from said first chamber, and transferring the resulting fluid mixture of intermediate temperature through said fluid path into said sec-0nd chambers while removing and storing heat from said fluid during said transfer; and

(d) withdrawing fluid from said second chambers through said fluid path into said low-pressure reservoir thereby effecting, expansion and'cooling of said fluid insaid second chambers and said fluid path, said fluid during said withdrawing receiving said heat previously stored in said fluid path.

References Cited by the Examiner UNITED STATES PATENTS 2,567,454 9/51 Taconis 62-6 2,907,175 10/59 Kohler 626 2,966,035 12/60 Giflord 62-6 3,119,237 1/64 Gifford 62-6 WILLIAM J. WYE, Primary Examiner. 

1. A METHOD OF PRODUCING REFRIGERATION WITH AN ENCLOSED SPACE DIVIDED INTO FIRST AND SECOND REFRIGERATING CHAMBERS AND A THIRD DRIVING CHAMBER, EACH OF VARIABLE VOLUME, COMPRISING THE STEPS OF (A) SUPPLYING HIGH-PRESSURE FLUID FROM A HIGH-PRESSURE FLUID SOURCE INTO SAID THIRD CHAMBER WHILE SIMULTANEOUSLY INCREASING THE VOLUME OF SAID FIRST AND SAID THIRD CHAMBERS AND DECREASING THE VOLUME OF SAID SECOND CHAMBER, SAID FIRST AND SECOND CHAMBERS BEING CONNECTED BY A FLUID PATH; (B) SUPPLYING HIGH-PRESSURE FLUID TO SAID FIRST CHAMBER FROM SAID HIGH-PRESSURE FLUID SOURCE WHILE CONTINUING TO SUPPLY HIGH-PRESSURE FLUID TO SAID THIRD CHAMBER AND COMPRESSING SAID FLUID IN SAID FIRST CHAMBER THEREBY CAUSING RESIDUAL FLUID IN SAID FIRST CHAMBER TO INCREASE IN TEMPERATURE; (C) WITHDRAWING HIGH-PRESSURE FLUID FROM SAID THIRD CHAMBER INTO A LOW-PRESSURE RESERVOIR WHILE SIMULTANEOUSLY DECREASING THE VOLUMES OF SAID FIRST AND THIRD CHAMBERS, INCREASING THE VOLUME OF SAID SECOND CHAMBER, CONTINUING TO SUPPLY HIGH-PRESSURE FLUID FOR MIXING WITH THE HIGH-PRESSURE FLUID OF INCREASED TEMPERATURE FROM SAID FIRST CHAMBER, AND TRANSFERRING THE RESULTING FLUID MIXTURE OF INTERMEDIATE TEMPERATURE THROUGH SAID FLUID PATH INTO SAID SECOND CHAMBER; AND (D) WITHDRAWING FLUID FROM SAID SECOND CHAMBER THROUGH SAID FLUID PATH INTO SAID LOW-PRESSURE RESERVOIR THEREBY EFFECTING EXPANSION AND COOLING OF SAID FLUID IN SAID SECOND CHAMBER AND SAID FLUID PATH. 